Mike Hughes, a 64-year-old stuntman who set out to test the Earth's shape, has died while attempting to fly a steam-powered rocket for a television series. Hughes was widely known as “Mad Mike” for his mixture of courage and refusal to accept the spherical nature of the planet. The tragedy is a reminder that conspiracy theories have consequences, and sometimes even apparently harmless ones can be fatal.

Hughes built steam-powered rockets, which he attempted to ride. His eventual goal was to reach the Karman line, 100 kilometers (62 miles) above sea level, considered by some the beginnings of space. On Saturday, he was attempting a more modest goal of 1,500 meters (5,000 feet), but even this was too much when his parachute failed to open properly.

A full coroner's inquiry will no doubt reveal more, but it is thought the gravitational forces of the launch knocked Hughes unconscious, leaving him unable to release the parachute on the way down, and back-up chutes also failed to deploy. Hopefully, this at least means Hughes didn't suffer.

Hughes injured himself during a 2014 flight to a height of about a kilometer.

Other flights were more successful.

The roughly spherical shape of the Earth has been know since the ancient world, demonstrated first by the shape of the Earth's shadow on the Moon during eclipses, and then by the differences in the angle of the Sun at the same time across latitudes. The latter discovery even allowed fairly accurate estimates of the planet's circumference 2,300 years ago. Dozens more proofs have subsequently emerged, ranging from compasses to the existence of GPS.

In an age where people have worked out we're being lied to about a lot of things, however, some people have become convinced that everything from authority is a lie. Where others with the same doubts look out the windows of planes or conduct tests with torches, Hughes was one to always take things to the next level.

Hughes' status as a self-proclaimed daredevil started long before his belief in the flatness of the Earth. After his death, his publicist Darren Shuster told the Los Angeles Times Hughes was actually aware of the world's true form. “I don’t think he believed it. He did have some governmental conspiracy theories. But don’t confuse it with that flat Earth thing. That was a PR stunt we dreamed up.”

From a publicity point of view, the idea certainly worked. Shuster attracted sponsors both from flat Earth believers and companies seeking to ride the infamy of his efforts. He was being filmed by, of all places, The Science Channel when he died for a series called Homemade Astronauts. In a trailer for the series, Hughes said: “People ask me why I do stuff like this. Basically, it’s just to convince people they can do things extraordinary with their lives.”

Hopefully, the lesson from this modern-day Icarus is that you can do extraordinary things, but safety requires listening to the best scientific and engineering advice.